DESCRIPTION: The surface ectoderm directly overlying the developing optic vesicle gives rise to two stratified epithelial tissues of the eye, the corneal epithelium and the crystalline lens. Early morphogenesis of the lens vesicle and further development and differentiation of the ocular epithelia involve tightly regulated mechanics of cell determination and differentiation. the nature and specific role of regulatory molecules controlling these gene expression programs are largely unknown. Recent evidence in the literature suggests that a family of transcription factors known as AP-2 (Activating Protein - 2) factors, are necessary for craniofacial morphogenesis. preliminary findings from this laboratory suggest that transcription factor AP-2 (Activating Protein 2) plays an important role in eye development, specifically regulating genes involved in morphogenesis of the lens and corneal epithelium. The proposed study will test the hypothesis that AP-2 transcription factors regulate gene expression programs that determine: a) early pattern formation of the lens vesicle and b) later stages of development and differentiation of the corneal epithelium and ocular lens. Determination of the expression pattern of three AP-2 proteins (a, B, y) in the differentiating and regenerating ocular epithelia using immunolocalization and in situ hybridization techniques will enable us to compare with the location of candidate downstream genes. To investigate the specific functional requirement of the AP-2a gene during morphogenesis of the lens vesicle, a detailed morphological examination of the ocular defects of AP-2a-/- knockout mice will be performed. In addition, the newly derived Lens complementation system (LCS) will be used to directly determine whether AP-2A is required for formation of the lens. To determine the specific role of AP-2 factors during lens fiber cell and corneal epithelial differentiation. AP-2 activity will be targeted in transgenic mice and in vitro culture models. Using a wild-type P-2 minigene and dominant negative minigenes designed to interfere with AP-2 activity, AP-2 activity will be altered in living cells in vitro and in transgenic mice in order to determine how AP-2 regulates specific aspects of epithelial cell biology, including cell adhesion.